body * {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: Arial, Helvetica, sans-serif;
}

main {
  min-height: 100vh;
  display: flex;
  justify-content: center;
  align-items: center;
}

#drawer {
  position: absolute;
  top: 0;
  height: 100vh;
  width: 50vw;
  left: -50vw;
  padding: 20px;
  background-color: #eee;
  border: solid 1px #000;
  transition: all 0.5s;
}

#drawer.open {
  left: 0vw;
}